冀北崇礼红旗营子黑云斜长片麻岩的地质地球化学特征

基于当代红旗营子群是否应该解体这一观点,研究了崇礼红旗营子群中黑云斜长片麻岩的地质地球化学特征。研究表明原岩为泥质沉积岩,其特点为SiO2〉56％,Al2O3〉MgO,Na2O〉K2O,Na2O／（Na2O＋K2O）〉0．5,且其他氧化物与SiO2含量呈现出有规律的变化,随着岩石中SiO：含量的增加,TiO2,AL2O3,FeO,Fe2O3,MgO,CaO,Na2O和K2O呈明显下降趋势。稀土元素总量较低;轻重稀土分离程度较高,LREE／HREE的值为5．16～7．98,La。／Yb。的值为4．28～8．62,轻稀土富集,重稀土平坦分布,稀土配分曲线表现出中等程度的负Eu异常,δEu的值为0．73～0．83。稀土元素Ce基本无异常或略显负异常,表明其形成环境可能为一浅海相或边缘海或被陆地封闭海。     

企业生态与涉农企业的发展研究

涉农企业的发展对加速我国农业结构调整，提高农民整体收入具有重要的意义。从企业生态角度分析了目前影响涉农企业发展的社会、经济和自然等因素，并针对影响企业发展的障碍提出了相应的对策。     

太原市冲积平原区包气带防止潜水污染的分析

根据戈里德别尔格提出的确定敏感性指数的思路，应用模糊评判法对太原市冲积平原区包气带防止潜水污染的敏感性进行了定性分析，并在此基础上提出了相应的防治措施。     

关于有限温SU(3)格点规范理论相结构问题的研究

应用变分累积展开方法研究SU(3)格点规范理论相结构,对有限温各向同性和异性SU(3)格点规范模型的Polyakov线,计算到第三级.结果表明:当维数D3时有层相存在,且在高温下夸克是解禁的.     

超密集网络中基于分簇的干扰管理方案

在超密集网络中,全频复用能够提升网络的吞吐量,但是导致了严重的基站间干扰。为了降低基站间干扰,首先通过干扰权重值描述小基站间的干扰程度,建立合理的干扰图;然后将分簇问题转化为Max K-Cut问题,利用改进的次优化启发式算法对小基站进行分簇;最后通过信道分配算法为每个簇中的用户分配子信道。仿真表明,本文的干扰管理方案在降低小基站间干扰的同时,能够提升系统的频谱效率和平均吞吐量。     

Characterization of PM2.5/PM2.5-10 and source tracking in the juncture belt between urban and rural areas of Beijing

Coarse （PM2.5-10） and fine （PM2.5） atmospheric particulate samples were collected in summer and winter during 2005-2007 in the juncture belt between urban and rural areas of Beijing. Elements, ions, organic/elemental carbon （OC/EC） and polynuclear aromatic hydrocarbons （PAHs） were determined to obtain some latest information about the particulate pollution in the juncture belt of Beijing. Particulate matter levels at this site were high as compared with the levels at other sampling sites in Beijing. Pollution elements, secondary ions and PAHs were enriched in fine particles rather than in coarse particles. An obvious seasonal variation of the chemical composition of PM was observed. Source apportionment results showed that secondary components were the largest mass contributor of PM2.5, accounting for 28%; whereas soil-related sources were the largest contributor of PM2.5-10, explaining about 49% of the total mass. The abnormal levels of soil heavy metals at the electronic waste disassembly site in the upwind villages suggested the potential impact of such activities to the environment.     

Apoptosis induced by titanium dioxide nanoparticles in cultured murine microglia N9 cells

Owing to the rapidly increasing output of nano-scale titanium dioxide （TiO2） particles, their potential risk for central nerve system （CNS） has elicited much concern recently. Microglia is the resident macrophage in CNS and essential for the homeostasis of the CNS microenvironment. They are supposed to response to nanoparticles depositing in the brain tissues. Therefore, we investigated the cytotoxic effects of TiO2 NPs on microglia N9 cells in vitro. Results of propidium iodide/fluorescein diacetate （PI/FDA） double staining and MTT test clearly showed that TiO2 NPs more efficiently affected the viability of microglia N9 cells. Further Hoechst 33258 staining and flow cytometric analysis proved that nano-scale but not normal scale TiO2 induced apoptosis in vitro, These data suggest that TiO2 NPs can elicit apoptosis of N9 cells in vitro and thus present a potential risk for CNS.     

SiCp／ZA-27复合材料SiC颗粒预处理工艺研究

对ＳｉＣ粒子进行子多种预处理工艺试验,得出ＳｉＣ粒了在９２０℃高温焙烧氧化,再在ＨＦ酸（１．５ｖｏｌ．）％）与丙酮混合液、丙酮中清洗球磨工艺是较优的预处理工艺。应用搅熔铸造工艺,处理后的ＳｉＣ颗粒能较易分散到含镁的ＺＡ－２７合金流中,用ＳＥＭ、ＥＤＳ、ＸＲＤ和ＴＥＭ测定和分析了预处理前后ＳｉＣ表面状态,得出ＳｉＣ颗粒表面物理,化学吸附的气体是阻止其分散进入ＺＡ－２７合金流的主要原因,ＳｉＣ表面的微     

浅谈货车列检单车技术检查发展及优化建议

货车列检技术作业标准中,单车技术检查作业过程是货车列检技术作业的核心内容之一,是规范列检检修作业,实现列检检修作业标准化,提高列检检修质量,确保列车运行安全的重要技术保障。文中阐述了列检单车检查技术的发展历程及作用,分析了列检单车检查技术亟待解决的问题,并对存在的问题提出了针对性的建议。     

非因子化方法研究B~-→π~0π~-衰变过程

本文用 QCD因子化和光锥 QCD求和规则系统地计算了 B- →π0 π- 衰变过程的强子矩阵元和分支比 ,其计算结果与实验相一致 .